ATT Materials Finer Than No. 200 Sieve (Washing Test)

Question 1

Which ASTM standard governs the test for materials finer than the 75-µm (No. 200) sieve in mineral aggregates by washing?

Accepted Answer

ASTM C117

Answer

ASTM C117 is the standard test method for materials finer than 75-µm (No. 200) sieve in mineral aggregates by washing.

Question 2

What is the minimum sample size for a washing test on a fine aggregate (maximum size 3/8 in.) per ASTM C117?

Accepted Answer

300 g

Answer

ASTM C117 requires a minimum sample mass of 300 g for fine aggregate with a maximum size of 3/8 in.

Question 3

During the ASTM C117 washing test, the aggregate is washed over which sieve to capture all fine material?

Accepted Answer

No. 200 (75 µm)

Answer

The wash water and suspended fines pass through the No. 200 (75-µm) sieve, retaining only particles coarser than 75 µm.

Question 4

After washing, the retained aggregate must be dried to a constant mass at what temperature range?

Accepted Answer

110 ± 5°C (230 ± 9°F)

Answer

ASTM C117 specifies drying the washed sample to constant mass at 110 ± 5°C (230 ± 9°F), the standard oven-dry temperature for aggregates.

Question 5

The percentage of material finer than the No. 200 sieve by washing is calculated using which formula?

Accepted Answer

(A − B) / A × 100

Answer

The formula (A − B) / A × 100 gives the percent passing No. 200, where A is the original dry mass and B is the dry mass after washing.

(ATT) ACI Aggregate Testing Technician Practice Test